Fig. 9

Structural observations and data from the Piz Terri-Lunschania Zone in the Val Scaradra region. a Distribution of measured stretching lineations (green marks) and fold axes (red marks) of the D2 phase. b Phengite gneiss 0.5 km west of Alpe Scaradra di sotto (R: 718,940, H: 157,876). View of the X–Z plane of D2 (Leis Phase). σ-type quartz porphyroclasts in a phengite-rich matrix point to sinistral (top-W) shear sense. c Phengite gneiss with C′- type shear bands indicating sinistral shear sense (width of sample 5 cm). d Thin section of mylonitic phengite gneiss (R: 719,228, H: 158,155) under crossed polarizers cut parallel to X–Z plane of the D2 phase (foliation 342/81, stretching lineation 066/28, width of thin section 6.9 mm). Components are mainly quartz and phengite. C′- type shear band points to top-SW shear sense. Triple junctions of quartz grain boundaries indicate post-kinematic annealing similar to sample VF41